Heating apparatus



D 1936- E. A. SWEELEY ET AL HEATING APPARATUS Filed Nov. 15, 1935 3Sheets-Sheet l lhwentors w m w 5. U M

attorney 1366- 1936; E. A. SWEELEY ET AL HEATING APPARATUS Filed NOV.15, 1935 3 Sheets-Sheet 2 lunentors Gttorneg w w w 05 Km. u Eou a My 0Patented Dec. 22, 1936 UNITED STATES PATENT OFFICE HEATING APPARATUSApplication November 15, 1935, Serial No. 50,052

17 Claims.

This invention relates to heating apparatus, and more. particularly to aheating device for use in heating storage chambers to protect stored ortransportation loads of fruits and other perishable commodities againstinjury or damage due to freezing or undesired low temperatures.

While the heating system of this invention is especially suited to theheating requirements of railway refrigerator cars, it is obviouslyadapted for other uses and purposes, and may be employed for heatingcars, trucks, ships, and storage houses, generally.

During periods of cold and freezing weather, refrigerator cars areusually provided with heaters to maintain the air in the merchandise orlading chambers at such temperature as will insure the desiredprotection to the shipment of perishable commodities. The heaters of theprior art, however, are open to the serious objection that they do notmaintain all parts of the lading chamber at substantially the sametemperature or at the desired temperature. In many instances, thisobjectionable feature is principally due to the fact the heaters dependon natural circulation and draft for the air which warms the chamber.With such practice, the circulation of air is relatively slow, and theair is much warmer adjacent the ceiling than near the floor, since thewarmest, and therefore lightest, air rises to the top of the room andgradually forces the colder (and heavier)- air downwardly. As a result,in an effort to warm the lower part of the shipment to the minimumpermissible temperature, the part of the lading just below the ceilinghas frequently been raised to a temperature in excess of themaximumpermissible temperature. Accordingly, the upper part of the shipmentoften suffered injury and damage from overheating.

It is, therefore, an object of this invention to provide a heatingarrangement which will avoid overheating of any part of the shipment, asfor mechanical energy for operating an element toproduce a forcedcirculation of air through the heater.

A further object of the invention is to provide a railway refrigeratorcar with a heater that will draw air from the upper part of the ladingchamber into the heater, and forcibly expel the air in a heatedcondition from the heater, and into the space below the apertured falsefloor deck of 5 the lading chamber, so that the heated air will bedistributed along the length of the chamber and then rise through theapertured deck and the shipment.

Another object is the provision of novel means for operating theair-circulating fan or blower of a heater.

Another object is to provide a compact and self-contained heater unitfor heating and mechanically circulating the air passing through the mheater.

It is also an object to provide automatic means for controlling theoperation of the heater, so that it will supply heated air as requiredto maintain desired temperature conditions.

Another object is the provision of an improved 20 steam generator andcondenser system for an air heater.

A further object is to generally improve the construction of airheaters.

Other objects and advantages will be apparent from the followingdetailed description of the preferred embodiments of the invention.

In the accompanying drawings,

Figure 1 is a vertical longitudinal section through a railwayrefrigerator car, showing the improved heater as applied in the icebunker space of the car;

Figure 2 is a vertical longitudinal section through a railwayrefrigierator oar, showing the improved heater in the lading space;

Figure 3 is a top plan view on enlarged scale of a detail of Figure 1.

Figure 4 is a perspective view of one of the fanshaped air outlets shownin Figures 1 to 3;

Figure 5 is a perspective exterior view on enlarged scale of the heatershown in Figures 1 and 2;

Figure 6 is a view in elevation of the heater shown in Figure 5 withpart of the casing removed.

Figure 7 is a cross sectional view taken on lines l'| of Figure 5.

Figure 8 is a cross sectional view taken on line 8-8 of Figure 7.

Figure 9 is a view partly in cross section taken on line 99 of Figure 7.

Figure 10 is a vertical cross sectional view taken on line Ill-l0 ofFigure 11.

Figure 11 is a bottom plan view of the thermostat shown in Figures 6, 7,9 and 10.

Figure 12 is a vertical cross sectional view of a modified form of drivefor the blower shown in Figure 7.

Figure 13 is a vertical cross sectionalview of a modified detail for theheater shown in Figures 6 to 8. a

Figure 14 is a vertical cross sectional view of a modified form or"heater, and is taken on line i ;li l of Figure 15.

Figure 15 is a cross sectional view taken on lines i5i5 of Figure 14.

Referring now to the drawings, Figures 1 and 2 illustrate the inventionas applied to' a railway refrigerator car of conventional construction.

I'he car has the-usual loading space or merchandise chamber 1, icechambers or bunkers 2 at each end, floor 3, and doorway shown in outlineat d. The car also has the usual end walls 5, ceiling 6, roof carlines'1, outside roof 8, and

outside top running board 9. The floor, side walls spaced from thewallsof the ice chamber by ,means of spacer posts'(not shown) to providevertical air channels l5.

Floor stringers l6 and slats II constitute a floor deck, raised somewhatabove the car floor, for supporting the lading, which deck may beremovably or permanently secured in place. The stringers are spacedapart transversely of the car, and together with the car floor 3 form aplurality of parallel channels l8 extending longitudinally of the carand from bulkheadto bulkhead. The slats H. are positioned transverselyof the stringers l6 and spaced apart to provide slots or apertures Hi.It will, therefore, be seen that.

air may circulate through and along the channels it formed by thestringers and floor, and that air may also pass from the channel spacesi8 into the merchandise chamber by way of the slots or apertures 19.

According to this imzention, the heater 201 when in use may bepositioned in the ice chamber 2 (see Figure 1), which is the generallyaccepted practice, or in the lading space I (see Figure 2).

In either case, the heater 2011s suitably anchored to the car by meansof chains M, or other appropriate securing means.

When the heater 20 is placed on the floor of the ice chamber, as inFigure 1, its heated air outlet (described later) may be connected to amanifold 22 provided with branches 23, each preferably having a flaredor fan-shaped end 24. The branches 23 may project through the bottomopening I3 of the bulkhead II, and each flared end 24 is disposed in oneof the air channels it formed betweenadjacent stringers l6 (see Figure3). The heater will circulate air through the car by forcing heated airinto the manifold 22,v and thence through the branches 23 and flaredends 24 into the air channels l8. The'heater is provided with means(described hereinafter) for forcing the air into the manifold, so thatwhen it enters the air channels it it will be distributed along thelength of same, while the flared ends 2d assist the air in spreadinglaterally along the channels i8. Thus, heated air will be distributed inall directions beneath the floor deck, and the openings l9 will permitthe heated or warmed air to rise throughout the entire floor area of thelading chamber. This heated air, due to its, low density, rises towardthe ceiling and in so doing circulates through and around the entirecargo. As the air nears the ceiling, it is drawn into the ice chambersby way of bulkhead openings i2 and then downwardly into the heater (forrecirculation) by the same means (referred to above and describedhereinafter) which expels the air from the heater and into the manifold22.

A heater 20 may be placed in each ice chamber if desired (as shown inFigure l) and the course taken by the circulated air, when two heatersare used, is shown by the arrows in Figure 1.

If the heater 20 is placed on top of the slats ill in the lading space,as shown in Figure 2, the heated air is delivered from the heater by wayof pipe 25, and a pair of distributor ducts 26 projecting in oppositedirections from pipe 25, positioned as within one of the channels it. Inorder that the air will spread laterally as within channel it, as wellas move longitudinally thereof, each duct 26 is preferably provided witha flared end 2%. From the space under rack slats I1, in which the ducts26 are positioned, the air rises through'the spaces or openings I9between the slats i1 and circulates through the cargo on its upward pathtoward the ceiling. As this air approaches and moves along the ceiling,it reaches the zone of down draft created by the heater, and is thendrawn downwardly into the heater for recirculation. The course taken byair during circulation, in the practice of this modifica- I or branches23 may be used. For example, the heater 20.may supply heated air, underforced circulation, into each air channel l8 as shown in Figures 1 and3, or into only one channel, as shown in Figure 2. Other suitablearrangements of air conducting pipes may be used, and any u arrangementis suitable that produces a general distribution of the heated 'airalong the floor of the car. Where only one channel l8 receives airdirectly as in Figure 2, part of this air will find its way into otherchannels before it ascends into contact with the cargo, as the air maypass from channel to channel by moving along the slots l9 when solidtype stringers I6 are used.

As shown in Figure 5, the heater 20 is constructed with a casing 21,formed by bending sheet metal or other suitable material intocylindrical'shape and securing the edges together with rivets 28, or byother suitable means. The top of the casing is provided with a removablecover 29 having a depending flange 30.

A cut-out portion or opening 3| in the casing 21 is adapted to be closedby a sliding door 32 having a handle operating member 33. The door isslidably mounted in vertical bent strips 34, riveted at 35 (or otherwisesecured) to the casing.

Horizontal strip 36, also secured to the casing, provides a bottom restfor the door, while inwardly bent ends 31 of strips 33 limit the upwardmovement of the door when uncovering the opening 3|.

A handle 4|, for carrying the heater, has its ends 42 bent to form eyesections, through which straps 39 pass. Clips 38, secured to the casing21,

of pins 40.

Openings 43 in the cover provide entrance for air to the heater, whileslots44 permit the escape of products of combustion coming from burners(described hereinafter).

Figure 6 shows the general arrangement of the apparatus within thecasing 21. A fuel tank A is located in the lower part of the casing, andsupplies fuel to the burner B, the flow of fuel being regulated by athermostat C. In the upper part of the casing, there is positioned aboiler D, to be heated by burner B, and supplying steam for operating aturbine E, mounted within a condenser F. A blower casing G, supportedbelow the condenser F, houses a rotary fan or blower (see Figure 7) thatis driven by the turbine E.

The details of the apparatus illustrated in Figure 6 are shown inFigures '7 to 11 and will now be described;

Referring to Figure '7, the fuel tank A is formed of top 46, bottom 41,and side walls 48, 49. The tank side wall 48 conforms to the shape ofheater casing 21 to fit tightly therein, while the tank bottom 41 restsupon the horizontal inturned flange 50 of a supporting ring 5| suitablysecured to the casing 21, as by riveting or bolting (not shown).

The burner B is mounted within the opening left between the tank sidewall 49 and the heater casing 21 and is preferably spaced from them toprovide an outer air passage 52 surrounding the burner. In order thatthe burner may utilize all of the fuel from the tank A, it preferablyhas its bottom at a somewhat lower level than the tank bottom, as shownin Figures 6 and '7. The burner is preferably of the annular type, beingprovided with inner and outer shells 53, 54 and a ring-shaped bottom 55to form an annular chamber for the main burner wick 56 and a centralflue space 51.

At the outer periphery of the burner, there is a chamber 58, ofcircular, triangular or other suitable shape, containing a pilot wick59.

Tank A may be filled through pipe 60 (see Figures 7 and 8), the latterhaving a cap 6|. Any suitable fluid fuel, such as alcohol may be used.During operation of the heater, tank A supplies this fuel to the chamberholding the burner wick 56 through pipes 62 and 63, and to chamber 58containing the pilot wick 59 through pipes 62, 64. A manually operablevalve 65 (of conventional design) in pipe 62 enables the operator tostop the flow of fuel from the tank A when the heater is not in use.

During operation of the heater, the valve 65 is set in the openposition, and the pilot wick 59 is constantly supplied, through pipes 62and 64, with sufiicient fuel to maintain a small pilot light adjacentthe top of the burner 5|. By raising the door 32, access may be had tothe pilot wick 59 for its igniting, or for extinguishing the pilotflame.

As shown in detail in Figures 10 and 11, the thermostat assembly C isprovided with a valve housing 66, connected to the ends of pipes 62 and63, so that fuel may flow into the housing bellows and the diaphragm 61.

from pipe 62 and leave by way of pipe 63. At' one end of the valvehousing, a flexible diaphragm 61 is held in place by a ring 68 and lip69 projecting from the housing. The diaphragm 61 carries, at one side, avalve stem 10, having a valve member 1| which, in the closed position,abuts a valve seat 12, as shown in Figure 10, to stop the flow of fuelinto the pipe 63. A spring 13, encircling the valve stem 10, andpositioned between the collar of valve stem 10 and the opposite end ofthe valve housing 66, tends to move the diaphragm to unseat the valvemember 1| to permit flow of fuel to burner wick 56 by way of pipe 63.

The thermostat assembly C is suitably supported in position below thefuel tank A. In the drawings, the support is shown as formed from v asingle piece of metal to provide a ring 18, horizontal members 14,branches 11, flanges 16 and bent portions 15 (see Figs. 9 to 11). Thissupport is secured to the tank bottom 41 (see Figure 9) by means of itsflanges 16 and to the valve housing 66 by means of the bent portions 15.The stationary ring 18 is suitably apertured to receive the head 19 of abellows 88. The opposite end of the bellows 80 is movable and carries aplate 8|. A stem 83 extends between the movable end of At one end, thestem 83 is secured to the plate 8| so as to move therewith, while at itsother end, the stem 3) 83 is fitted into a cup-shaped member 85 havingthreaded engagement within a sleeve 86, mounted on the diaphragm 61.

The bellows 80 contains an expansible fluid, (preferably a gas) which,when heated, expands to force the stem 83 carried by plate 8| againstdiaphragm 61. The latter then moves against the action of spring 13 toseat the valve member. 1|, as shown in Figure 10. When the bellowscollapses, due to contraction of its fluid on cooling, the bellows 88moves to release stem 83. Then spring 13 will move the diaphragm 61 andthe valve stem 10, to unseat the valve member 1|.

The screw threaded engagement between the member 85 and sleeve 86provides an adjustment for changing the travel of the stem 83 in openingand closing the fuel supply valve, so that the thermostat may be therebyregulated to operate at predetermined temperatures.

It will now be seen that when the temperature of the air in the lowerpart of the heater falls below a predetermined minimum temperature, thethermostat will automatically operate to permit the flow of fuel toburner wick 56, and that it will be ignited by the pilot light. When thetemperaturein the lower part of the heater rises above a maximum desiredtemperature, the thermostat will either cut off or appropriately reducethe flow of fuel to the burner wick 56, in order to maintain a desiredtemperature.

The thermostat may be placed in the lower end of the heater, which iscloser to the car floor, so it will respond to temperatures prevailingadjacent the car floor. The thermostat will therefore respond to thetemperature of a cold part of the car, and will insure that all parts ofthe lading space are kept above a minimum low temperature.

In order to protect the thermostat assembly, there is provided, as shownin Figure 9, a removable, flexible, cover 81 having flanged edges 88,which are received in grooves formed by bent strips 89 and tank bottom41, to which-strips 89 are secured. When it is desired to adiust orrepair the thermostat, the cover 81 may be removed 75 by forcing thesides together so that its edges 88 will move out of engagement withstrips M.

As shown in Figures '7 and 8, the boiler D is constructed with anannular boiler chamber, formed of inner and outer shells 98, 9E, andringshaped end walls 92, 93, providing a central flue space at. An outercasing 95 is spaced from shell 9! by means of spreaders 96 (see Figure8) so as to provide an outer flue space 9?, surrounding the boilerchamber.

If desired, another form of boiler may be used to eliminate the centralflue. At the top of the boiler, a hood 98 is mounted on top of thecasing 95, the latter being encircled by the depending flange 99 of thehood. A cap N10 is supported by straps I0! over the opening m2 in thehood 98. The products of combustion coming from burner B and collectingunder the hood 98 will pass through opening I02, between straps WI andunder cap Hill, which will deflect these gases so that part will passdownwardly in the heater'while another part may rise and leave theheater by way of slots t4.

A pipe I03, extending through hood 98, and valve I04 provide convenientmeans for filling the boiler with water (see Figure 7).

The condenser F is composed of top H05, bottom ")6, curved side wall 501and straight side wall I08. Spreaders I09, secured to side wall lll'l,space the condenser wall away from the casing 21, and to position thecondenser so that substantially its entire exterior surface will beexposed to cooling eifect of the downdraft of air entering the heaterthrough openings 43 in the cover 29.

The spreaders I09 also serve as cooling fins for dissipating the heat ofthe condenser.

Blower casing G, rigidly secured to the bottom I06 of the condenser, isprovided in its lower wall with a circular air intake opening H0. An airoutlet or discharge pipe I, connected to the blower casing provides ablower exhaust opening leading to the outside of the heater unit. Anarrow strap H2, secured across the center of the intake opening i I 0,has a conical recess to provide a bearing for the pointed lower end of ashaft H3. The blower fan lid is securedto this shaft M3 by means of aset screw, or other fastening means, and receives support from a nut or[bearing 8 l5 also secured to the shaft 8 H3.

The upper end of shaft H3 extends through the top of the blower-casingand into the condenser F. A sleeve H6, encircling the shaft H3 has itsbase welded to condenser bottom we to provide a steam and watertightjoint. A packing nut lll, of any conventional design provides a steamand watertight joint between the top of .sleeve I Hi and shaft H3. Theshaft H3 is supported from the condenser bottom and below the turbine E,to avoid binding of the shaft as might be the case if a support wereplaced on the upper end of the shaft and secured to the top condenserwall.

The turbine or rotor wheel E is secured to the shaft M3 by means of akey or set screw, and a by the downdraft of air in the heater, whereuponthe steam condenses into water and collects in the bottom of thecondenser.

When the pressure in boiler D has been sufilciently reduced, due to thethermostat 0 cutting off or diminishing the flow of fuel to the burner56, the water in condenser F returns by gravity to the boiler D throughpipe l2 6 strainer fl22, a conventional type one-way check valve H23,and pipe i126.

A relief pipe we having a safety valve H26 is connected to the condenserF for regulating its steam pressure. Abnormal pressure in the boiler andcondenser will be relieved by the safety valve The heater shown indetail in Figures 5 to 11 having been placed and secured in a railroadcar, as shown in Figure 1 or 2, has its outlet pipe ill suitablyconnected to manifold 22, as in Figure 1, or to pipe 25 as in Figure 2.Door 32 is raised and fuel having been fed to pilot wick 59, the latteris ignited. The operation of the heater will then be automatic, and willeffectively maintain the temperature'of the space or chamber of its usewithin a desired range over a relatively long period of time. When thetemperature of the air adjacent the lower end of the heater and beneathfuel tank A falls below a predetermined temperature, thermostat Cautomatically establishes communication between pipes 62 and 63, so thatfuel will flow from tank A to wick 56 to be ignited by the pilot lightabove wick 59. The

source of combustion air for the burner flame depends on whether thelower end of the heater is closed or open. If the lower end is closed,as when the heater is placed on an imperforate floor, air is drawn fromthe upper part of the heater and under the casing to the burner. If thelower end of the heater is open, as when the heater is placed on a.grating or 'deck rack, a limited amount of air will pass up flue spaces5'? and 52 to support the burner combustion;

The burner flame and products of combustion will pass upwardly throughboiler flue spaces 94 and 9'! to heat water in the annular boilerchamber for generating steam. The products of combustion are deflectedoutwardly by cap I00, part going down into the heater while part mayrise through slots 44. The steam generated in boiler D operates theturbine E, which in turn through the intermediary of shaft H 3 drivesthe blower fan i IQ. Operation of the fan or blower i I produces adowndraft of air, in the upper part of the heater, so that air entersthrough the apertures 43 and is heated by direct contact with the boilercasing 95 and condenser F before being drawn into the blower casing G byway of intake opening l m. The air drawn into the blower casing isdischarged through pipe Ill. When the temperature of the air in andadjacent the lower part of the heater rises to a predetermined point,the thermostat C cuts off the flow of fuel to the burner wick 56, andthe pressure in boiler D is rapidly lowered. This drop in boilerpressure permits condensed steam in the condenser I" to return to theboiler for reuse. As the boiler and condenser are part of a closedsystem, it is only necessary to replenish the supply 9f water atinfrequent intervals. f

Figure 12 shows a modified form of turbine drive which may besubstituted for that shown in Figures 6 to 8', without changing theother parts or the general operation of the heater. In thisconstruction, a ball type of turbine I27 having nozzles E28 is securedto a shaft i29 having an axial steam passage I30. A sleeve I 3I, weldedto the condenser bottom I06, and having an upper flange I32, provides abearing surface and steam packing for the lower end of the turbine ballI21. A hollow fitting I33, having threaded connection to the end of pipeI I9 provides a support for the upper end of shaft I29. Steam fromboiler D (see Figures 6 to 8) is conducted to the interior of fittingI33 by pipe I I9. From the fitting, the steam passes through ports I34,hollow space I30 in shaft I29 and ports I35 into the interior of theturbine ball I21. The steam then issues from the nozzles I28, and thereaction from its discharge rotates the turbine and shaft I29 carrying ablower fan at its lower end in the same manner as shaft .I I3 in Figure7.

Figure 13 illustrates a modified arrangement for the turbine E, blowerH4, and driving shaft II3. These parts operate as in Figures 6 to 8, buthave been rearranged so that the shaft I I3 is supported in a horizontalposition, and extends through condenser wall I08, on which the blowercasing G is mounted. The turbine E is driven as in Figures 6 to 8 andblower fan II4 draws air in through intake I I and expels it through theside of the casing as in Figures 6 to 8. Instead of a gravity-flowreturn for the condensed steam shown in Figures 6 to 8, a force-feedreturn is illustrated in Figure 13. An eccentric I36, secured to shaftII3, drives a strap I31 connected to the rod I38 of piston I39, so thatthe piston will be reciprocated upon rotation of the turbine shaft II3.Piston I39 reciprocates within a cylinder I40, having connection with apipe I4I, leading from condenser F to the boiler. Conventional one-wayvalves, indicated diagrammatically at I42, allow water to be drawn intocylinder I40 from condenser F on the intake stroke of piston I39 and tobe forced into the boiler chamber from cylinder I40 on the deliverystroke of the piston. This construction provides for return of condensedsteam while the boiler is under pressure.

Figures 14 and 15 show a modified heater unit, which may be used in amerchandise chamber or refrigerator car in the same manner as the heatershown in Figures to 11. In this construction, the fuel tank A, burner B,thermostat C and fuel supply connections are the same as in Figures 6 to8, except that the shape of the burner is oval in cross section. Othershapes for the boiler, however, may be used if desired, the oval shapebeing used in this unit in order to use available space while avoidinginterference with other elements ofthe unit.

The boiler chamber I43 and boiler housing I44 are both of oval shape(the outline of the housing being shown in Figure 15), and theseelements are spaced apart to provide a flue space I45 in communicationwith an oval-shaped flue I46 leading to an outlet opening I41 in thecover 29. To maintain the burner, boiler and boiler housing in theirrelative positions, the boiler housing has downwardly bent flanges I48which fit over the burner B, and shoulders I49 which are supported bythe edge of the top of tank A. A door 32, and opening I50, in housingI44 permit access for igniting the pilot, when it is desired tocondition the unit for its intended automatic operation.

A partition I5I is fitted within the heater casing, and turned upflanges I52 and I53 thereof define a crescent-shaped aperture (seeFigure 15) through the partition. A condenser chamber I 54, mounted uponthe partition I5I, is provided with a removable handhole cover I55,having screw thread engagement with a ring I 56 secured in the topcondenser wall. On either side, the condenser I54 is provided withhollow extensions I51 (see Figure 15), from which project arcuatecondenser pipes or tubes I58 closed at their outer ends I59. Condenserchamber I54 and condenser pipes I58 present a relatively large area ofheat radiating surface for contact with the air to be warmed, and thetotal area of heat radiating surface is further increased by mountingfins or plates I60 on pipes or tubes I58. Two standards I6I, I62 withinthe condenser chamber support the ends of a. strip or bar I63, whichlatter carries a pointed bearing I64, adjustably held in place by a nutI65. A housing I66 secured to and depending from the under side ofpartition I5I, supports a blower casing I51. The air inlet I69 to theblower casing is at its under side, and a spider or bar I68 extendsacross this opening, the bar having a conical recess I10, to afford abearing for the lower end of a shaft "I which extends through partitionI5I and has its upper end engaging bearing I64 near the top of thecondenser casing. Where the shaft I1I passes through the partition I5Iand condenser bottom, a sleeve I12 and packing nut I13 surround theshaft to provide a water and steam-tight joint between the shaft and thebottom of the condenser chamber I54.

The turbine wheel I14, and blower fan I15 are each secured to andsupported by the shaft I1I, so that the fan will be driven upon rotationof the turbine wheel I14. During its operation, the fan draws airthrough intake I69 and forces it out clrfmthe heater casing through thedelivery pipe Steam for operating the turbine I14 is conducted fromboiler chamber I 43 by pipe I11 and standard I62, which is hollow forthis purpose, to a nozzle I18 projecting from the upper end of thestandard. The nozzle I18, which may have a flattened end, directs thesteam in a manner to impinge upon the rotor and to thereby drive theturbine I14. After passing the turbine, the steam circulates in thecondenser tubes I 58, where is condenses, due to the large heatradiating surface presented by the tubes I 58 and fins I60. Thecondenser tubes I58 are inclined toward the condenser chamber I 54, andthe condensed steam flows by gravity into the latter. With theconstruction of this modification, it is found the steam is condensedrapidly, and that the boiler may therefore operate at a relatively lowpressure, which is an important consideration for this'type of heater.

During operation, blower fan I15 creates a circulation of air throughthe heater. Air to be heated is drawn into the heater through apertures43, arranged in cover 29, as shown by Figure 5 and moves toward thecrescent-shaped opening in the partition I 5I defined by the flanges I52and I53. The arrangement of the apertures 43 and the crescent-shapedopening is such that the air in passing from the former to the latterwill come'in contact with and be heated by the outer surfaces of thecondenser chamber I54, extensions I51, tubes I 58, fins I60 and flueI46. From the crescent-shaped opening the air passes downwardly and alarge part is further heated by contact with boiler housing I44, beforethe air is drawn into the blower casing I61 by way of intake openingI69. The air, now in heated condition, is expelled from the blowercasing by way of pipe I 16, which corresponds in purpose and function topipe III shown in Figures 6 to 8.

A pipe H9 opening into the condenser chamber 354 has its lower endwithin the boiler I83 for returning condensed steam. Conventionalpacking I88 and packing nut i8l are provided for sealing the jointswhere the pipe H9 passes through the partition It and the boiler housingI48, respectively. A steam pipe I82 extending through the interior ofpipe H9 has its upper end near the top of condenser chamber I54 and itslower end terminating within the lower end of pipe W9. A sleeve I83,having an enlarged head $88 secured at its upper end to the housing M8,surrounds the lower end'of pipe 679 and carries a guide 985 for the stemE86 of ball valve E87.

Steam in boiler N53 has access to the interior of the open-ended sleeveI83 and acts on the lower side of valve it? to seat it against the endsof both pipes W8 and E82, shaped and positioned to fit the valve. Aswater collects in condenser B58, it passes downwardly through pipe H9,and around pipe i182, until stopped by a valve I87. At the same time,the air or steam pressure in condenser H8 is communicated to the valveit? through pipe I82. Water is therefore returned to the boiler duringits operation, whenever the pressure exerted on top of the ball valvel8? by the head of Water in pipe H9 and steam or air in pipe 9 and steamor air in pipe H82 exceeds the pressure exerted on the bottom of thevalve by the steam in boiler I43.

Since the condenser and boiler are in a closed system, and the condensedsteam is returned to the boiler, the necessity of replenishing the waterof the system is minimized. However, when necesary, feed water may beintroduced into the filling pipe I88 leading to the boiler chamber.

While water and steam are mentioned for use in the closed fluid systemherein disclosed, it is to be understood that equivalent fluids can beused, without departing from the spirit of the invention or the scope ofthe appended claims.

A further feature of the heater shown in Fig tires 14 and 15 is that thepartition l5! with its flanges I52 and E53 will trap and collect anymoisture which may condense on and drip from the condenser pipes I58 andfins I88.

' It will be understood that while the invention is particularlyapplicable to railroad refrigerator cars, it ofiers obvious advantageswhen practiced in connection with other types of railway and roadvehicles including so-called ventilator cars, box cars, express cars,and motor trucks, as well as ships and in storage houses.

Only preferred embodiments of this invention have been shown anddescribed, but other forms and modifications embodying the invention.may be readily devised within the spirit and scope of the invention, asdefinedv by the following claims.

What we claim is: I

1. In combination with a merchandise chamber having means fordistributing heated air therein adjacent to and along its floor toprovide horizontal and upwardly flowing streams of warm air efiective tomaintain a protective temperature for the merchandise in said chamber, aportable,

self-contained heater unit comprising mechanically operated means todraw air to be heated from said chamberinto the unit from above and toexpel the said air therefrom into said distributing means, means to heatthe air duringits passage through the unit, whereby air is drawn fromthe upper part of said chamber and distributed in heated conditionadjacent the floor of said chamber, and means responsive to ambienttemperatures of the chamber for controlling the operation of the heaterunit.

2. In combination with a merchandise chamber having a load supportingdeck spaced above its floor with ventilation openings therethrough toprovide for circulation of air, means for distributing heated air withinsaid chamber and beneath said load supporting deck to provide horizontaland upwardly flowing streams of warm air effective to maintain aprotective temperature for the merchandise in said chamber, and aportable, self-contained heater unit comprising mechanically operatedmeans to draw air to be heated from said chamber into the unit fromabove and to expel the said air therefrom into said distributing means,means to heat the air during its passage through the unit, whereby airis drawn from the upper part of said chamber and distributed in heatedcondition adjacent the floor of said chamber, and means responsive toambient temperatures adjacent the floor of the chamber for controllingthe operation of the heater unit.

3. In combination with a merchandise chamber having a load supportingdeck spaced above its floor with ventilation openings therethrough toprovide for circulation of air, means for distributing heated air withinsaid chamber and beneath said load supporting deck to provide horizontaland upwardly flowing streams of warm air efiective to maintain aprotective temperature for the merchandise in said chamber, and aportable, self-containedheater unit comprising mechanically operatedmeans to draw air from the said chamber into the unit from above and toexpel the said air therefrom into said distributing means beneath theload supporting deck, means to heat the air during its passage throughthe unit, whereby air is drawn from the upper part of said chamber anddistributed in heated condition adjacent the floor of said chamber,means for converting part of the heat energy produced in the unit intomechanical energy for operating said mechanically'operated means, andthermostatic means responsive to ambient temperatures adjacent the floorof the chamber for controlling the operation of the heater unit.

4. In combination with a vehicle for transportation of perishablecommodities, the vehicle having a merchandise chamber in which a loadsupporting deck is spaced above the floor of the chamber and the saiddeck is provided with ventilation openings therethrough for circulationof air, a portable self-contained heater unit for maintaining aprotective temperature for the commodities in said chamber, the saidunit comprising a mechanically operated element for drawing air to beheated into the unit from above and discharging said air'in horizontallydirected streams beneath the said deck, means for heating the said air'in its passage through the unit,

,means for converting a part of the heat energy developed in the unitinto mechanical energy for operating the said element, and meansresponsive to ambient temperature in the chamber adjacent its floor forcontrolling the operation of the heater unit.

5. In combination with the lading chamber of a railway vehicle, the saidchamber being constructed for the stowing of perishable merchandise andhaving a load supporting deck spaced above the floor with ventilationpassages therethrough and beneath the same, a portable self containedheater unit for maintaining a desired temperature in said chamber, thesaid unit comprising mechanically operated means to draw air to beheated from said chamber into the unit from above and to expel the saidair beneath said deck for upward movement through saidventilatingpass'ages to maintain a protective temperature for themerchandise in said chamhorizontal and upwardlyflowing streams of warman effective to'maintain a protective temperature for the merchandiseinsaid chamber, a portable, self-contained heaterunit comprising a casinghaving an air inlet through'which air to be heated is drawn'froni saidchamber into the unit from "above and an air outlet through which heatedair is discharged into said distributing fmeans, me-

chanically operated means to provide circulation ofair fromsaidair'inlet to said air outlet, means to 'heat'the air during itspassage'through the unit,'wherebyf air is drawn from the upper part ofsaid chamber and distributed in heated condition adjacent the floor ofsaid chamber, and

means within the casing responsive to temperature for controlling theoperation of the heater unit.

5 '2'; In'combination with a. merchandise chamber having means fordistributing [heated air therein adjacent to and along its floor to,provide horizontal and upwardly flowing streams of warm airefiect'ive'to'maintain a protective temperature for the merchandise insaid chamber, a portable, self-contained heater unit comprising a fluidfuel burner, a fuel reservoir connected to said burner. for supplyingfuel thereto, means responsive to ambient temperatures for controllingthe flow of fuel to said burner, a closed fluid system includinga boilerheated by said burner and a condenser to receive steam from said boiler,an operating element within said system positioned to be driven by thesteam generated in said boiler, and a blower operated by said elementfor drawing air from said chamber into the unit from above for heatexchange contact with the elements of said system and for discharge ofheated air into said distributing means whereby air is drawn from theupper part of said chamber and distributed in heated condition adjacentthe floor of said chamber.

8. A portable self-ccmtained heating unit for use in merchandisechambers to maintain perishable commodities stored therein at aprotective temperature, comprising mechanically operated means to drawair to be heated into the unit from above and to expel the said air fromthe unit, means for discharging the heated air in a horizontal directionadjacent the floor of the chamber to be heated to produce a desireddistribution means for discharging the heated air in a horizontaldirection adjacent the floor of thechamber to be heated to produce adesireddistribiltion of heated air, means to heatthe air during itspassage through the unit, means for converting a part of the heat energydeveloped in the unit into mechanical energy for driving said first-menwtioned means, and means responsive to ambient temperatures of airadjacent the base of the unit for controlling the operation of theheating unit.

10. A portable self-contained heating unit for usein merchandisechambers to maintain perishable commodities stored therein at aprotective temperature, comprising a fluid fuel burner, a fluid fuelreservoirconnected with said burner for supplying fuel thereto, saidburner ELUCIIGSQIF voirbeing arranged side by side and in the lower partof the heating unit, a fluid heating system arranged in the upperpart ofsaid unit, said system including a boiler heated by said burner and acondenser receiving steam from said boiler,,

mechanically operated means forproducing a forced draft of air into andthrough the heating unit for heat exchange contact with the elements ofsaid system, means operated by the steam generated in said boiler fordriving said draft producing means, and temperature responsive means forcontrolling the operation of the heating unit.,

11. A portable self-contained heating unit for use in merchandisechambers to maintain perishable commoditiesstored therein at a,protective, temperature, comprising a fluid fuel burner; a-

fluid fuel reservoir connected with said burner for supplying fuelthereto; a closed fluid system including a boiler to 'be heated by saidburner, a condenser, and connections for.

- use in merchandise chambers to maintain perishable commodities storedtherein at a protective temperature, comprising a fluid fuel burner; afluid fuel reservoir connected with said burner for supplying fuelthereto; a closed fluid system including a, boiler to be heated by saidburner, a condenser, and connections for supplying said condenser withsteam from said boiler and returning condensed steam to said boiler;mechanically operated means to return said condensed steam to saidboiler; mechanically operated means for producing a forced draft of airinto and through the heater unit for heating by heat exchange contactwith the elements of said system; means operated by the steam generatedin said boiler for driving both said draft producing means and saidcondensed steam returning means; and temperature responsive meansadjacent the base thereof for controlling the operation of the heatingunit,

13. A portable self-contained heating unit for use in merchandisechambers to maintain perishable commodities stored therein at aprotective temperature, comprising a casing, a fluid fuel burner, afluid fuel reservoir connected with said burner for supplying fuelthereto, said burner and reservoir being positioned side by side and inthe lower part of said casing, a boiler positioned above said burner tobe heated thereby, a condenser connected to said boiler to receive steamtherefrom, said boiler and condenser being arranged in the upper part ofsaid casing, a turbine mounted within said condenser and adapted tobedriven by steamvfrom said boiler, and a blower mounted within thecasing and positioned therein to be driven by said turbine forestablishing air flow through said casing and for bringing air to beheated into heat exchange contact with the heated elements of said unit,said casing being constructed to permit said blower to draw air into thecasing and to expel the air in heated eondi tion from the casing.

14. In a portable self-contained heating unit for use in merchandisechambers to maintain perishable commodities stored therein at aprotective temperature, the combination comprising a fluid fuel burner;a fluid fuel reservoir connected with said burner for supplying fuelthereto; and a closed fluid system including a boiler heated by saidburner, a condenser connected with said boiler to receive steamtherefromv and to return condensed steam thereto, means driven by steampassing-from said boiler to said condenser, a pressure responsive valvecontrolling a gravity flow return of condensed steam to said boiler, andmeans providing for exposure of one side of said valve to the steampressure in said boiler and for direct exposure of part of its oppositeside to the steam pressure in said condenser and-of another vpart ofsaid opposite side 'to the pressure exerted by the weight of thereturning condensed steam, whereby the condenser steam pressure willsupplement the gravity action of the returning condensed steam inunseating said valve to permit return of condensed steam while theboiler is under pressure.

15. A portable self-contained heating unit for use in merchandisechambers to maintain perishable commodities stored therein at aprotective temperature, comprising a fluid fuel burner; a fluid fuelreservoir connected with said burner for supplying fuel thereto; aclosed fluid system including a boiler heated by said burner, a chamberfor' collecting condensed steam, condenser tubes positioned to receivesteam from said chamber and to return thereto condensed steam, andconnections for supplying said chamber with steam from said boiler andreturning condensed steam to the boiler; mechanically operated means forproducing a forced draft ofair into and through the heater unit for heatexchange contact with the elements of said system including the saidcondenser tubes; and means operated by the steam generated in saidboiler fordriving said draft producing means.

16. A portable self-contained heating unit for use in merchandisechambers to maintain perishable commodities stored therein at aprotective unit for heat exchange contact with the elements of saidsystem including said fins and condenser tubes; and means operated bythe steam generated in said boiler for driving said draft producingmeans.

17. In a method for providing a protective temperature for commoditiesstored in a merchandise chamber having a load supporting deck providedwith ventilating openings and spaced above the chamber floor, the steps'comprising creating. a downdraft to withdraw air from said chamber andadjacent the ceiling thereof, heating the withdrawn air in its downwardcourse, and discharging the heated air in horizontally directed streamsbeneath the load supporting deck to secure a distribution of heated airbeneath the deck and rising streams of heated air throughout asubstantial portion of the chamber- EDWARD A. SWEELEY.

RALPH KILLINGSTAD.

